advertisement


Solar Panel "Voltage Optimisers"

Ewen1970

Ewen1970

The Ocean Doesn't Want Me
Any wise heads on here know much about these things?

My 90 year old Dad has just had a company "sell him the pitch" that one of these will stop the inverter of his solar panels being damaged because of high voltage in his area (244 volts).

This sounds like BS to me and the little bit of research on line suggests the same. "Not quite a scam" seems to be how it's best described.

£2400 is the charge for one of these things.

Snake Oil me thinks, but would appreciate any wisdom offered here.

I've told him to cancel the installation...
 
Sounds like BS to me as well.

My brother deals with renewable systems including Solar Panels, I`ve sent him a message and I`ll let you know his response.
 
When we installed our system, we used a single inverter system as opposed to micro inverters on each panel. Since we have a single inverter we added optimizers to each panel. This is done because if you don't have optimizers, then for each string of panels, all the panels on the string will be power limited by the lowest producing panel, so if you have one panel shaded it will compromise the system power.

Perhaps the price quoted was to add optimizers to each panel? I would ask for an exact breakdown of what they would be installing along with part numbers of what they would be installing.
 
Seconded. This is a scam. The OP's dad has a single inverter in his system, and the claim is that "high" mains voltage will damage it. No it won't.

Your "240 V"* supply is almost never at that exact voltage, so 244 shouldn't be a surprise. Mains voltage across the whole of western Europe is only guatanteed to lie between 216 and 253 V... frequency is much more tightly controlled.

All mains electrical equipment certified for use in the UK is designed to work with that wide voltage range. Driving its output at 244 V cannot damage the inverter, because that voltage is within the range of AC voltages it was designed to supply.

The device being sold does do what it claims to, but a domestic customer has no use for one. They are primarily sold to factories who require a more exact AC voltage to opimise the efficiency of plant machinery. Unless your dad's electric bill is a couple of grand a month, he'll never see any benefit from power conditioning.

__
* officially the UK mains voltage is 230 V.. plus 15% minus 6%, replacing the old standard of 240 V ±6%. There was no actual change of generated voltage in most places.. the aim of the "change" was to have a single nominal voltage, "230 V", that covered every European country's supply voltage, so that equipment makers didn't have to make multiple versions of products for different countries.
 
Sounds like BS
UK grid connect inverters must be certified to G83
240v Auto switch off for high voltage & Auto switch off for underrvoltage
£2400 better spent on new high efficiency inverter / micro invertor per panel if system is old for higher outputs

UK comply with the requirements defined in engineering
recommendation G83/1. These setting cannot be changed by an installer, user or by any other person
without the use of a tool (password protected).

• Power quality
• Harmonic current emissions as per BS EN 61000-3-2 A
• Voltage fluctuations and flicker as per BS EN 61000-3-3 A
• DC injection / Power factor
• Under / Over frequency switch off
• Under / Over voltage switch off
• Loss of mains test
 
Panels are DC. AC Power is not going anywhere near those panels. As was mentioned earlier, optimisers handle panel shading issues, again DC side though.
 
paulc said:
Panels are DC. AC Power is not going anywhere near those panels. As was mentioned earlier, optimisers handle panel shading issues, again DC side though.
Click to expand...
But what are they? Transformers? Regulators? Anyone got a circuit diagram?

The optimisation would appear to be mostly to the bank account of the installation tech
 
@Ewen1970 : your instinct is right: avoid, avoid; avoid.

Sanity check: NO manufacturer goes into the Grid-tied Inverter business - and all the necessary, incredibly expensive Type-Approvals and EMC emissions for diff markets -testing requirements - while out for a quick buck expecting to dismiss Warranty claims. And no Installer, is going to supply shonky boxes for the later Warranty reason also.


SO:
Yes - total scam, first.
Second - @Dan K - these things are comparatively-weedy AC bucking transformers sold at high cost that'll never , ever be recovered; and discussed here before a couple of times. Totally worthless for ...reasons I can regurgitate if anyone really wants to know.
 
MartinC said:
This is done because if you don't have optimizers, then for each string of panels, all the panels on the string will be power limited by the lowest producing panel, so if you have one panel shaded it will compromise the system power.
Click to expand...

Panels are wired up as a few parallel strings. If a panel is shaded, it doesn't produce much current and limits the current of that entire string. There is not much you can do about it, maybe bypass the shaded panel, if the remaining panels in that string are producing enough power. Avoiding getting a panel in deep shade is very important
 
davidsrsb said:
Panels are wired up as a few parallel strings. If a panel is shaded, it doesn't produce much current and limits the current of that entire string.
Click to expand...
There are inverters like the SolarEdge that run all panels in parallel, we have one and would always recommend them for new installs but replacing an existing inverter would only be worth it if the current one is not working properly.
 
Most new panels have three bypass diodes by now, which means partly shaded areas are automatically blocked.

A good inverter will constantly scan for the best Voltage to Amp ratio and will be immune to a few panels shaded of.

I know for sure SMA and Kostal do this.
My SMA has 22 Panels (South) on one string and 5 (East) on another. A church oppodite my house, or rather the curch tower results in quite a bit of shade every day, passing over all panels within about 2h. Plus the 5 eastern panels are shaded of completely after 15h.

Both effects are barely visible in my daily ouput curve.
 
gingermrkettle said:
There are inverters like the SolarEdge that run all panels in parallel, we have one and would always recommend them for new installs but replacing an existing inverter would only be worth it if the current one is not working properly.
Click to expand...
You need to put panels in big arrays in series to keep currents and cable sizes under control, also inverter efficiency will improve with higher input voltage.
 
This was my brother`s reply to my email, I hadn`t realised that he doesn`t do grid connect.

"Yes they do exist for grid connect stuff, but I don't know a lot about them. They are fitted directly to each solar panel (like a max. power point tracker) to optimize each panels DC output, so I'm not sure how that would regulate the mains voltage. They also need the grid connect inverter to be optimiser compatible. The plus side is, they should increase the output of the system by an average of 12% ish. Is it worth retro fitting them? Probably not due to the expense, especially if the inverter needs changing. So not BS."

Not as informative as I had hoped - sorry Ewen.
 
The OP's father is not being sold DC optimisers for the panels, but rather a single "optimiser" for the home AC supply on the spurious basis that the home AC supply voltage is "too high".

The solar inverter angle is a variation of an existing scam selling these devices with promises of "cheaper bills" or preventing "damage" to home appliances.
 
Exactly that @KrisW

Have told my Dad to cancel the appointment and refer them to me if there as an issue.

The actual report basically says very little.

Wiring: Good
Panels: Good
Voltage: 244
Recommend: VO

What the report doesn’t say is what the sales guy said to him.

“Increased voltage as a result of new housing developments means that it will damage his inverter which will cost him £7,000”.

To a 90 year old who has had 3 strokes.

Criminal.

Thank you all for your wisdom and support.

Ewen
 
Just for reference, a brand new solar inverter would cost about £2000—2500, fitted. There's no way you could do £7k damage to one.
 
KrisW said:
Just for reference, a brand new solar inverter would cost about £2000—2500, fitted. There's no way you could do £7k damage to one.
Click to expand...

You could get a 150kW inverter for that, maybe he has a large house!

Wrt damage from overvoltage our house ran in the 250V range when the transformer had a problem and the inverter was fine.
 
dweezil said:
You could get a 150kW inverter for that, maybe he has a large house!

Wrt damage from overvoltage our house ran in the 250V range when the transformer had a problem and the inverter was fine.
Click to expand...
Yes, I was giving a worst-case cost for replacement.. it was just to show that the idea that you can do £7k of damage to one of these is nonsense.
 
You must log in or register to reply here.


advertisement


Back
Top